1. Field of Invention
This invention relates generally to methods for the manufacture of multiple-pane sealed glazing units and more particularly of units that incorporate decorative features that simulate the appearance of leaded or stained glass panels, and also to units products by such methods.
2. Description of the Prior Art
In U.S. Pat. No. 5,494,715 issued to Glover, there is a description of the various efforts that have been made in recent years to improve the energy efficiency and condensation resistance of multiple-glazed sealed units. These improvements include: low-e coatings, argon or krypton gas fill, narrow width cavities and insulating spacing-and-desiccant systems for perimeter edge seals.
As noted in the U.S. Pat. No. 5,494,715, there is also a growing consumer interest in heritage window features with one popular feature being leaded or stained glass panels. Traditionally, these panels have been made by hand using grooved lead strips or cames. In the past because these handcrafted panels were very labor intensive to produce, various efforts have been made to simplify traditional production techniques and these efforts have been documented in the patent literature.
U.S. Pat. No. b 3,226,903 issued to Lillethun describes a triple-glazed sealed unit with a traditional stained-glass panel being incorporated as the center glass lite.
U.S. Pat. Nos. 4,335,170 and 4,438,165 issued to Butler describe a stained glass panel fabricated from a single glass pane where lead profiles are adhered in coincidental alignment to either side of a flat glass sheet. The extruded lead profiles are manually applied and are approximately 0.022 inches in thickness. Because of the stiffness and thickness of the lead profiles, the top lead profile has to be stretched and bent around the bottom lead profile and as a result, the process has to be carried out manually with each lead profile being individually applied.
U.S. Pat. No. 5,494,715 issued to Glover describes a triple pane unit with the center glass pane located only 1/8" away from the front glass lite. To create the visual illusion of a solid lead came, three thin stripes are applied. One stripe is applied to the cavity face of the front glass sheet and the other two stripes are applied to either side of the center glass sheet. Traditional lead cames are grey in color, and if all three decorative stripes are colored grey, experience has shown that because of various optical and shadow effects, the visual illusion of a traditional leaded pane window is not always convincingly created.
For the triple stripe method described in U.S. Pat. No. 5,494,715, one key potential advantage is that the production process can be automated with the objective of producing over a 1000 decorative glass units per eight hour shift. However, the horizontal production equipment described involves glass sheets moving below a multi-head bridge assembly and no automated method or technique is given for applying the stripes to the opposite side of the glass.